Radiation detection instrumentation can be broadly classified as gas-filled detectors, scintillators, and semi-conductors. Scintillators, in particular, are important because they are easy to use, and can provide information on a particle's energy. The main components of current scintillator-based detectors are the scintillation crystal itself and a photomultiplier tube (PMT), which includes photocathodes and dynodes. The photocathodes absorb low energy (near visible) photons created from interactions of the incident radiation with the crystal, and in-turn generate electrons (i.e., photoelectrons). Because the number of photoelectrons produced is proportional to the incident particle energy, these detectors can be used to detect and identify a radionuclide. Photocathodes typically have a maximum quantum efficiency of approximately 25%. Quantum efficiency is defined as the number of photoelectrons produced from the number of incident photons.Quantum Efficiency=(# of electrons generated)/(# of incident photons)
The other component of the PMT is the electron multiplication structure, which consists of dynodes that amplify the number of photoelectrons generated from the photocathode because their signal is so low. Photomultiplier tubes typically have about 106-107 gain at the anode for collection. They usually require anywhere from a few hundred volts up to thousands of volts. This configuration creates inherent disadvantages, include a high bias voltage, dynode fragility, and magnetic field effects (i.e., electron trajectories between dynodes are altered by EM fields). Accordingly, there is a need for new radiation detection technology.
New energy production and storage technologies also are important considerations. Energy transitions fluidly between mechanical, chemical, electrical, magnetic, radiant, and nuclear forms. Current devices and technological limitations prevent or impede exploitation of this feature, and energy that could be used for productive work is lost or inefficiently used. As demand for energy increases, the need for inexpensive and efficient ways to use energy becomes increasingly important.